Historically, when it was necessary to completely remove a disc from between adjacent vertebrae, the normal remedy was to fuse the adjacent vertebrae together. More recently, there have been important developments in the field of disc replacement, namely disc arthroplasty which involves the insertion of an artificial intervertebral implant into the intervertebral space between adjacent vertebrae and which allows movement of the adjacent vertebrae relative to each other in flexion, extension, lateral bending, axial rotation and translation, as well as absorbing axial compression.
One such development is an artificial intervertebral implant as shown in Published Application No. WO 01/01893, published Jan. 11, 2001. The instruments for inserting same are shown in Published Application No. WO 01/19295, published Mar. 22, 2001.
While the intervertebral implant and instruments as shown in these publications represents a substantial improvement in the art, there exists a continuing need for improvements in the field of artificial intervertebral implants.
One such area in need of further improvements includes intervertebral implants for the intervertebral spaces between adjacent cervical vertebrae. This is because the cervical vertebrae and the dimensions of the intervertebral spaces between them are quite small. For example, the area of the cervical vertebral surfaces facing the adjacent cervical intervertebral spaces may be only about 20 percent of the intervertebral surfaces of the vertebrae in the lumbar region, thereby making this an extremely delicate area in which to insert an intervertebral implant.